below/NavTest — pull request #1 by dhoepfl (2014-11-11 21:49:13+00:00)
Title: Auto-Layout constraint: Tob of NavBar to Top Layout Guide

Just had the same problem …

Make NavBarDelegate's positionForBar return UIBarPosition.TopAttached:

UIBarPositionTopAttached

Specifies that the bar is at the top of the screen, as well as its containing view.

Bars with this position draw their background extended upwards, allowing their
background content to show through the status bar.